Refrigerating apparatus



y 7, 1942- G. P. MARCY 2,288,818

REFRIGERATING APPARATUS Filed Nov 1, 1940 2 Sheets-Sheet l CI I12 lllllll a/msmu/c 35 2/ 9a "h 54 F16. f.

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Hlllllllll #5 FIG- l0. 1 INVENTOR E (A GERALD Q Mnecv July 7, 19420 G, MARCY 2,288,818

REFRIGERATING APPARATUS Filed Nov. 1, 1940 2 Sheets-Sheet 2 WITNESSES:

INVENTOR GERALD P. MARCY ATTORNZ? Patented July 7,1942

REFRIGERATING APPARATUS Gerald P. Marcy, Longmeadow, Mass, assignor to Westinghouse Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application November 1, 1940, Serial No. 363,842

2 Claims.

This invention relates to thermostatically-controlledswitches and more especially to a thermostatically-controlled switch adapted for installation on the cooling unit of a mechanical refrigof the thermostat for opening and closing the switch. and for locking the same in the open or closed position.

These and other objects are effected by my invention as will be apparent from the following description and claims taken in connection with the accompanying drawings forming a part of this application, in which:

Fig. 1 is a sectional view of the thermostatically-controlled switch of this invention;

Fig. 2 is a sectional view on the line II-II of Fig. 1;

Fig. 3 is a sectional view on the line III-III of Fig. 1;

Fig. 4 is a sectional view on the lineIV-JV of Fig. 1;

Fig. 5 is a plan view of bi-metallic actuating disc of the invention;

Fig. 6 is an elevation of the cam which closes the switch; 7

Fig. 7 is an elevation of the cam which opens the switch;

Fig. 8 is a plan view of the travel limiting disc of the switch;

Fig. 9 is a sectional view of the switch of this invention with the contacts locked in the closed position;

Fig. 10 is a sectional view of the switchwith the contacts locked in the open position; and,

Fig. 11 is a somewhat diagrammatic view of the switch of this invention installed in a domestic refrigerator.

Referring now to the drawings for a detailed description of the invention, the reference numeral l0 designates the frame of the thermostatically-controlled switch. The frame is formed of molded insulating material and comprises a lower cup-shaped member II and a disc-shaped upper member l2 provided with three legs i3 which rest on the lower member. Both members H and [2 have coaxial I4 and I5 and are clamped together by a metal clip l6 comprising 'a ring-shaped base ii and three upwardly-extending arms l8 at-the edges of the base IT. The base l1 engages the lower edges of the member II and the three upwardlyextending arms I8 lie in grooves on the outer side of the legs l3 of the member l2. The upper ends of the arms are turned inwardly and downwardly to engage a shoulder l9,- formed in the outer edges of the disc-shaped portion of the member l2. 1

The inner edge 2| of the ring-shaped base I! of the metal clip 16 is depressed to form a seat for a circular, bi-metallic disc 22 which forms the operating element of the thermostatically-controlled switch. The disc 22 has a centrally located opening 23 and is slightly dished so that the central portion thereof snaps upwardly or downwardly in response to changes in temperature, the upwardly-snapping action taking place when the temperature decreases below a certain degree.

A switch blade 24 is located within the frame It). It comprises a thin strip of metal, one portion of which is bent downwardly into a U configuration and its end 23 is provided with two oppositely-extending lugs which are secured to the lower member H by rivets 21. The free end of the switch blade 24 is provided with an electric contact which engages with a second and lower electric contact 3| secured to the lower frame member H by a rivet pin 32 integral with contact 3| and extending through the lower memher I l. The switch blade 24 has an opening 33 positioned above the central opening 23 of the disc 22 and an operating rod 34 extends through both 01' said opening 23 and 33 to transmit the motion of the disk 22 to the switch blade 24 to open and close the contacts 29 and 32.

The operating rod 34 comprises a lower discengaging portion 35 of metal, a. central'switchopening portion 36 of electrical insulating material, and an upper switch-closing portion 31, also of electrical insulating material. The lower portion includes a threaded shaft 38 which extends through the central opening 23 in the disc 22 and is secured to the edges of the same adjacent said opening 23 by two nuts 33 and 4|, one on each side of the disc 22. The lower nut 4| has araised neck 42 which extends through the central opening 23 and engages the upper nut 33. The lower portion has an axial and upwardlyextending pintle 43 which engages an axial openvertical central openings ing 44 in member I2 is threaded to of the knob the base of the central portion 36 to hold the same in a coaxial position. The'central portion 36 also has an axial pintle 44 which extends upwardly through the opening 33 in the switch blade 24. The upper portion 31 is ringj shaped, rests on the switch blade 24, and engages the pintle 44 projecting through the opening 33 thereof. The switch blade 24 is thus clamped betweensthe upper surface of the central portion 36 and the lower surface of the upper portion 31 of the operating rod 34, both of said surfaces being convex to afiord maximum angular movement to the switch blade 24.

The central portion 36 of the operating rod 34 has a circumferential cut forming neck 45 which engages a slot 46in the center of an upwardly dished disc 41 clamped between the ringshaped base I1 of the metal clip I6 and the base of the lower frame member II. The central slot 46 of the disc 41 communicates with a larger opening 48 in the disc 41 through which the lower operating rod portion II is inserted when assembling the switch, to effect the engagement of the neck 45 of the lower rod portion II with the slot 46. The neck 45 of the lower rod portion II is longer than the thickness of the disc 41 to permit limited axial travel of the operating rod 34.

The central opening -I of the upper frame engage the threads of an adjusting spindle 49. The spindle 49 has an axial bore, the upper portion 5| of which is of smaller diameter than the lower portion 52. The' upper portion 5| has an internal thread which engages an adjusting screw 54 which extends downwardly into the enlarged portion 52 of the bore. The lower end of the adjusting screw 54 is bluntly pointed and engages a conical depression formed inthe upper surface of a plunger 56, to afford substantially frictionless rotation on said'plunger 56. Both the plunger 56 and the upper portion 31 of the operating rod 34 have shoulders formed thereon which engageopposite ends of a compression spring 6|.

The upper end of the spindle is slotted to form two upstanding prongs 62 which fit into cooperating depressions in the base of the cylindrical knob 64. The knob 64 also has a central hole through which the upper endof the screw 54 extends. ,A cap nut 61 engages the upper end of the screw '54 to secure the knob 64 tightly on -end of a two nuts 66 which engage the threads formed above the shoulders 19 of thespindle 49. p The rim of the cup-shaped rubber bellows is provided with an outwardly-extending bead 61, which bead lies adjacent the shoulder I9 cut in the outer circumference of the disc of the member I2 and is secured on said shoulder I9 by an inwardly-extending bead 66 rolled in the side wall of the casing 1| to tightly clamp the bead 81 of the rubber bellows 6| between the rolled bead 66 and the shoulder I9.

The bellows is provided with a sidewardly-extending sleeve 9| which passes through the slot 14 of the side of the metal casing 1| and a rubber covered cable 92 and 94 is secured in said sleeve 9| by two clamping rings 95, one of which is secured on the inside of the casing 1| and the other to the outer side thereof. The clamping rings 95 also secure the cable in position relative to the casing 1|. One of the conductors 93 of the cable 92 is secured to the upper end of the metallic strip 96 which passes through an opening 91 in the upper frame member I2 and the lower end of which issecured to the switch blade by one of the rivets The other conductor 94 is secured to one similar metallic strip 96 which passes through an opening 99 in the frame member I2 and the other end of which is secured to the contact 3|. When the switch is closed, a continuouselectrical conducting circuit'is'thus established between 94, through the two metallic strips 96 and 96,

the switch blade 24, and the two contacts 29.

thereof.

The temperature at which the disc snaps upwardly or downwardly varies according to the tension of spring 6|. The tension of this spring 6| may be varied by either one of two means.

the prongs 62 of the spindle 49 The purpose a cup-shaped upper portion thereof and the lips 15 of the casing 1| are turned outwardly, for engagement with a cover 16. A metal heat-conducting bracket 11 is brazed to the casing II, which bracket is adapted for securement to an evaporator 18 of a mechanical refrigerator to secure the ther- .mostatic switch thereto.

The upper portion of the spindle is of reduced external diameter to provide shoulders 19 and is threaded for a portion of its length immediately above the shoulders 19. The space between the spindle and the casing is sealed by a cupshaped rubber bellows 6|, the central portion 62 of which is depressed and provided with a censecured '75 tral opening 63, the edges of which are against theshoulders '19 bya washer 65 and by holding nut 61 switch.. After this adjustment is made, the ad- The first means is a factory accomplished by turning the central adjusting screw 54 in the spindle 49 by means of the screw driver slot I66 formed in the upper end of the screw 54. This adjustment is made beforethe is secured to the thermostatic justing screw is secured in the spindle by soldering I61 and the adjusting knob 64 and the holddown nut 61 are secured in place. Thereafter.

the adjustment for temperature is effected only by turning the knob 64, which turns the entire adjusting spindle 49 in the threaded opening of.

the upper frame member I2 and raises or lowers the spindle 49, together with the plunger 56, in accordance with the screw threads on the spindle 49. Movement for rotating the adjusting spindle 49 is provided by the flexibility of the rubber bellows 6|. The knob is provided with an indicator pointer I66 and the cover 'of the casing with indicia' (not shown) which cooperate with the pointer I66 to indicate the position of the knob 64.

The switch mechanismv also provides for manual movement of the contact to either the open or the closed position and the locking of the contact 29 in either of said positions. To eflect this result, two O-shaped strips of metal III carrying the conductors 93 the two conductors 93 and adjustment and is I ergy through leads 93, 94, and lil.

and I I2 are secured to the free end of the switch blade 24 adjacent the contact 29. The O-shaped strips III and H2 extend upwardly from the contact 29, andthe free ends of the strips II I and H2 face upwardly and toward the lower portion of the spindle 49, which portion has a ring of insulating material H3 secured thereon on which two cams H4 and H5 are formed diametrically opposite to one another, and one somewhat higher than the other, as best shown in Figs. 9 and 10. The upper cam H4 is provided with an inclined operating face II6 which, when the knob 64 is turned to one of its extreme positions, engages the free end of the C-shaped strip III, regardless of whether the contact 29 is open or closed and forces the contact 29 to the closed position, if open and retains the contact 29 in said position. This position is shown in Fig. 9. The engagement of cam II4 with the free end of the C-shaped strip III occurs preferably when the spindle 49 is turned to its lowermost position.

In a similar manner, and as best seen in Fig. 10, the lower cam II5 engages the free end of the c-shaped strip II2 to open the= contact 29 and lock the same in the open position, preferably when the spindle 49 is rotated to its extreme upper position. It will be observed that the opening and closing force exerted by the cams H4 and H5 is transmitted substantially directly to the contact 29 and is not transmitted through the disc 22, so that if the contact 28 freezes for example, in the closed position, and

the disc 22 cannot open the same, a strong force can be transmitted substantially directly to the contact 29 to break it open.

The switch of this invention may be used in refrigerating apparatus as shown in Fig. 11 in which thereference numeral I2I represents a cabinet having an insulated chamber I22 in the upper portion thereof and a machine compartment I23 below the insulated compartment I22. An evaporator I8 is mounted in the upper portion of the insulated chamber I22 and the thermostatic switch of this invention is mounted adjacent and in heat exchange relationship with the evaporator I8.

The refrigerant supplying apparatus is located in the machine compartment I 22 and comprises a compressor I24 driven by an electric motor I25. The compressor I24 withdraws refrigerant vapor from the evaporator I8 through a suction tube I26, and forces it through a tube I2I to a condenser I28 wherein the vapor is liquefied and then returned through a capillary impedance tube I29 to the evaporator I8.

The electric motor I 25 receives electrical en- The thermostatic switch of this invention is interposed between the leads 93 and 84 and opensand closes the contact 29 when the temperature of the evaporator I8, as transmitted to the disc 22 through the casing II and the bracket I1,

rises or falls to the limits at which the disc 22 is set to snap upwardly or downwardly. The moisture or frost which normally collects on the evaporator I8 will not interfere with the operation of the thermostatic switch because of its sealed construction.

It will be apparent from the above that this invention provides an adjustable and sealed thermostatic switch adapted for installation in moist or freezing atmospheres. The invention further provides means in such a switch for forcibly moving the contacts in the open or closed pcsition and locking the same in said positions.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without depart-,

ing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are specifically set forth in the appended claims.

What I claim is: 1

1. In a thermostatically-controlled switch mechanism, the combination of a cup-shaped casing, switch elements therein, a bimetallic, snap-acting temperature-responsive element in said casing adapted to open and close said switch elements, a rotatable spindle having a portion within said cup-shaped casing and a second portion projecting therefrom, said spindle being operatively connected with said temperature-re-. sponsive element to vary its temperature response in accordance with the rotation of said spindle, and a flexible, moisture-proof membrane secured across the mouth of the cup-shaped casing, and about thespindle to allow rotation thereof, said membrane, spindle, and cup-shaped casing forming a portion of a sealed housing containing the switch elements, the temperatureresponsive element, and portions of said spindle.

2. In a thermostatically-controlled switch mechanism, .the combination of a cup-shaped casing, switch elements therein, a current-conducting wire connected with each of said elements, said wires projecting from the mouth of the cup, a bimetallic, snap-acting temperatureresponsive element in said casing adapted to open and close said switch elements, a rotatable spindle having a portion within said cup-shaped casing and a second portion projecting therefrom, said spindle being operatively connected with said temperature-responsive element to vary its temperature response in accordance with the rotation of said spindle, and a flexible, moisture-proof membrane secured across the mouth of the cupshaped casing, about the spindle and about said and said wires, the membrane being of sufilcient flexibility to allow rotation of said spindle.

. GERALD P. MARCY. 

